1. Field of the Invention
The present invention relates to a feeding apparatus for plate-form parts such as lead frames, etc., and more particularly to a claw-drive mechanism used in such a feeding apparatus.
2. Prior Art
For example, the apparatus described in the Japanese Patent Application Laid-Open ("Kokai") No. 60-67313 is one of conventional plate-form part feeding apparatuses. In this prior art apparatus, respective female screws are fastened to frame feeder assemblies which have claws that feed lead frames, and these female screws are screw-engaged with a male screw.
In this apparatus, since female screws are fastened to frame feeder assemblies and screw-engaged with a male screw, an extremely long male screw is required. In addition, it is difficult to manufacture such a long male screw with high precision and to design the frame feeder assemblies with high precision.
The object of the present invention is to provide an apparatus for feeding plate-form parts such a lead frames in which a male screw or drive shaft which is shorter than a conventional male screw can be used so that a respective frame feeder assembly of the feeding apparatus can be moved precisely.
The object of the present invention is accomplished by a unique structure that includes (a) a plurality of frame feeder assemblies which have claws that are used to feed plate-form parts, (b) a slider to which the frame feeder assemblies are mounted, (c) a female screw (moving piece) connected to the slider, (d) a male screw (drive shaft) screw-engaged with the female screw (moving piece), and (e) a claw moving motor which rotates the male screw (drive shaft).
With such a structure, when the claw moving motor is rotated a fixed amount, the male screw (drive shaft) rotates and the slider moves a fixed distance together with the female screw (moving piece). As a result, the frame feeder assemblies attached to the slider also move a fixed distance.
Thus, since the frame feeder assemblies are mounted on the slider, and the moving piece is attached to this slider, the length of the drive shaft which moves the moving piece needs only to be as long as a fixed distance necessary for the frame feeder assemblies to be moved, i.e., as long as the feeding pitch of one plate-form part to be fed. In other words, since the drive shaft can be very short, the respective frame feeder assembly can be moved with high precision.